Semiconductor device obtained by dividing semiconductor wafer by use of laser dicing technique and method of manufacturing the same

ABSTRACT

A semiconductor chip is formed by dividing a semiconductor wafer by use of the laser dicing technique. The semiconductor chip has a laser dicing region on the side surface thereof. A dummy wiring layer is formed along the laser dicing region on the surface layer of the laser dicing region. A laser beam is applied to the dummy wiring layer to divide the semiconductor wafer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2003-006387, filed Jan. 14,2003, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a semiconductor device and a manufacturingmethod thereof and more particularly to a laser dicing technique forapplying a laser beam to divide a semiconductor wafer into, discretechips.

2. Description of the Related Art

It is predicted that a microprocessor now used is required to process afurther larger amount of information at high speed in future. So far,miniaturization of transistors determines the performance of themicroprocessor. However, in recent years, RC delay (R: Resistance, C:Capacitance) causes a problem and much importance is given not only tominiaturization of transistors but also to parasitic capacitance(capacitance between wirings arranged with an insulating materialdisposed therebetween) and resistance of wirings which connecttransistors to one another.

In order to suppress the RC delay, it becomes necessary to change awiring material from Al to Cu and use a material with a small dielectricconstant instead of a silicon oxide film as an insulating material.However, the insulating film with the small dielectric constantgenerally has a porous structure and since the low dielectric propertyis acquired by virtue of the structure, the mechanical strength andadhesion strength thereof are extremely low in comparison with those ofthe silicon oxide film. Therefore, when a semiconductor wafer is dicedinto discrete chips, layer-layer separation tends to occur if theinsulating film with the small dielectric constant is mechanically cut.Further, since the Cu wiring (or copper conductor) is formed of amaterial having relatively high viscosity, film separation tends tooccur if a normal blade dicing process is performed.

Therefore, much attention is paid to laser dicing instead of theconventional blade dicing. In the laser dicing, a laser beam with highenergy is applied to melt and cut a semiconductor wafer. Therefore, itis expected that the cutting property of the Cu wiring and insulatingfilm with the small dielectric constant can be significantly enhanced incomparison with the grinding method such as the conventional bladedicing.

As the laser dicing, the following two methods are considered. The laserdicing methods are described in Jpn. Pat. Appln. KOKAI Publication No.2002-192367, for example. The first method is to apply a laser beamafter focusing the laser beam on the uppermost layer by use of a lens(condenser lens) 11 as shown in FIG. 1 and melt and cut a wafer 12together with a circuit element layer 13. The second method is to setthe focusing position of a laser beam on the internal portion of thewafer 12 to form a melt processing region 16 due to multiphotonabsorption as shown in FIG. 2 and then discretely divide the wafer 12 bystretching a dicing film 15.

Since the first method requires extremely large laser power when thethick wafer 12 is cut, larger damages will be applied to the wafer incomparison with a case of the blade dicing method in some cases.Therefore, the first method is suitable for a process of cutting onlythe circuit element layer 13 on the surface layer by use of relativelylow laser energy, for example.

Since the second method is to divide the wafer 12 starting from the meltprocessing region 16, it can cope with the relatively thick wafer 12.However, since insulating films and wiring layers (or inter-connections)are arranged in a complex form in the wiring pattern of the circuitelement layer 13 on the surface layer, there occurs a possibility thatunexpected destruction such as separation of the insulating film andlayer-layer separation of the wiring layers will occur at the time ofdividing Particularly, there occurs a strong possibility that insulatingfilms with small dielectric constant which are recently actively usedwill be destroyed at the time of dividing because of characteristicssuch as the low mechanical strength and low adhesion strength thereof.

That is, in the laser dicing, the surface state of a finished to-be-cutmember is largely influenced. More specifically, if focusing and poweradjustment are made on a region in which metal wiring layers are presentand the wafer is cut, large damage is given to a region in which nometal wiring layers are present and film separation occurs in the worstcase. Particularly, when a plurality of transparent films which permitthe laser beam to pass therethrough are laminated on a dicing lineregion, the damage becomes significant. On the other hand, if focusingand power adjustment are made on a region in which no metal wiringlayers are present, there occurs a possibility that the metal wiringlayer cannot be cut in some cases.

Therefore, when the laser dicing is performed, it is required to finelyadjust a laser dicing device according to the surface state of ato-be-cut member. However, since patterns of metal wiring layers such asalignment marks and test pads are arranged in a complicated form in thedicing line region of the actual semiconductor wafer, it is difficult toadjust and set the laser dicing device into an optimum state.

As described above, the conventional semiconductor device and themanufacturing method thereof have a problem that the surface state of afinished to-be-cut member is influenced when the laser dicing isperformed, the quality is lowered and the cutting property andmanufacturing yield are lowered.

BRIEF SUMMARY OF THE INVENTION

A semiconductor device according to an aspect of the present inventioncomprises a semiconductor chip having a laser dicing region on a sidesurface, and a dummy wiring layer formed along the laser dicing regionon a surface layer of the laser dicing region.

A semiconductor device according to another aspect of the presentinvention comprises a semiconductor chip having a laser dicing region ona side surface, and a laser absorption member formed along the laserdicing region on a surface layer of the laser dicing region.

A semiconductor device according to still another aspect of the presentinvention comprises a semiconductor chip having a laser dicing region ona side surface, an element region formed in the semiconductor chip,bumps formed on the semiconductor chip for connection with the exterior,a barrier metal layer formed between the bumps and external electrodesof elements formed in the element region, and a barrier metal layerformed along the laser dicing region on a surface layer of the laserdicing region on the side surface of the semiconductor chip.

A method of manufacturing a semiconductor device according to anotheraspect of the present invention comprises applying a laser beam to asemiconductor wafer except an alignment mark and testing pads formed ineach region between semiconductor chips of the semiconductor wafer, anddividing the semiconductor wafer into discrete semiconductor chips.

A method of manufacturing a semiconductor device according to anotheraspect of the present invention comprises focusing a laser beam on asurface layer side of a dicing line region, applying a laser beam to asemiconductor wafer except an alignment mark and testing pads formed ineach region between semiconductor chips to form a cut region shallowerthan thickness of the semiconductor wafer, focusing a laser beam on adeep layer side of the semiconductor wafer corresponding in position tothe cut region, applying a laser beam to the semiconductor wafer exceptthe alignment mark and testing pads formed in each region between thesemiconductor chips to form a melt processing region due to multiphotonabsorption in the semiconductor wafer, and dividing the semiconductorwafer into discrete semiconductor chips.

A method of manufacturing a semiconductor device according to stillanother aspect of the present invention comprises applying a laser beamfocused on a surface layer side of a dicing line region to asemiconductor wafer except an alignment mark and testing pads formed ineach region between semiconductor chips of the semiconductor wafer andapplying a laser beam focused on an internal portion of thesemiconductor wafer to the semiconductor wafer except the alignment markand testing pads formed in each region between the semiconductor chipsof the semiconductor wafer to form a cut region on the surface layerside of the semiconductor wafer and a melt processing region due tomultiphoton absorption on the deep layer side of the semiconductorwafer, and dividing the semiconductor wafer into discrete semiconductorchips.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a cross sectional view showing a laser dicing step of a firstmethod, for illustrating a conventional semiconductor device and amanufacturing method thereof;

FIG. 2 is a cross sectional view showing a laser dicing step of a secondmethod, for illustrating a conventional semiconductor device and amanufacturing method thereof;

FIG. 3 is an enlarged pattern plan view showing two chips formed closeto each other in a semiconductor wafer and a region between the twochips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a first embodiment of the present invention;

FIG. 4 is an enlarged pattern plan view showing two chips formed closeto each other in a semiconductor wafer and a region between the twochips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a second embodiment of the presentinvention;

FIG. 5 is an enlarged pattern plan view showing two chips formed closeto each other in a semiconductor wafer and a region between the twochips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a third embodiment of the present invention;

FIG. 6 is an enlarged pattern plan view showing two chips formed closeto each other in a semiconductor wafer and a region between the twochips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a fourth embodiment of the presentinvention;

FIG. 7 is an enlarged pattern plan view showing two chips formed closeto each other in a semiconductor wafer and a region between the twochips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a fifth embodiment of the present invention;

FIG. 8 is an enlarged pattern plan view showing two chips formed closeto each other in a semiconductor wafer and a region between the twochips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a sixth embodiment of the present invention;

FIG. 9 is a cross sectional view showing a first step of laser dicing,for illustrating a semiconductor device and a manufacturing methodthereof according to a seventh embodiment of the present invention;

FIG. 10 is a cross sectional view showing a second step of laser dicing,for illustrating the semiconductor device and the manufacturing methodthereof according to the seventh embodiment of the present invention;

FIG. 11 is a cross sectional view showing a laser dicing step, forillustrating a semiconductor device and a manufacturing method thereofaccording to an eighth embodiment of the present invention; and

FIG. 12 is a cross sectional view showing a laser dicing step, forillustrating a semiconductor device and a manufacturing method thereofaccording to a ninth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

FIG. 3 shows two chips (semiconductor chips) 21-1, 21-2 which are formedclose to each other in a semiconductor wafer and a region 22 between thechips 21-1 and 21-2 in an enlarged form, for illustrating asemiconductor device and a manufacturing method thereof according to afirst embodiment of the present invention. In a portion near the centralportion of the region 22, an alignment mark 24 and test pads 25-1, 25-2,25-3 are arranged. Further, laser dicing regions 23-1, 23-2 arestraightly arranged along the outer peripheries of the respective chips21-1, 21-2 to avoid the alignment mark 24 and test pads 25-1, 25-2,25-3. Wiring layers are respectively formed on the front surface layersof the laser dicing regions 23-1, 23-2. The wiring layers are not usedto make an electrical connection but used as dummy patterns (dummywiring layers) which make laser beam application regions uniform andpermit the laser beam to be easily absorbed. For example, the dummywiring layer is formed by using the same layer as metal wiring layersused in element regions of the chips 21-1, 21-2 together with thealignment mark 24 and test pads 25-1, 25-2, 25-3.

When the semiconductor wafer is divided into the discrete chips 21-1,21-2, a laser beam is applied onto the laser dicing regions (metalwiring layers) 23-1, 23-2 to melt and cut the laser dicing regions. Atthe time of melting and cutting, the focusing position of the laser beamis set on the uppermost layer by use of a lens and the laser beam isapplied to melt and cut the wafer.

Further, after the focusing position of the laser beam is set on theinternal portion of the wafer and the laser beam is applied to form amelt processing region due to multiphoton absorption, the wafer can bedivided into discrete chips by cracking or stretching a dicing film.

With the above configuration and manufacturing method, since the metalwiring layers are formed on the laser dicing regions 23-1, 23-2 and thesurface states thereof are uniform, the quality of the finished productwill not vary. Further, since the dummy wiring layer (metal wiringlayer) tends to absorb the laser beam, the cutting property in the laserdicing step can be improved. Of course, since the wafer is divided bymelting, there is no possibility that chippings occurring in the dicingstep in which a mechanical grinding process using a blade is performedwill occur. Further, focusing and power adjusting of the laser dicingdevice can be easily attained. In addition, since the alignment mark 24,test pads 25-1, 25-2, 25-3 and dummy wiring layers are formed by use ofthe same layer as the metal wiring layers used in the element regions inthe chips 21-1, 21-2, it is only necessary to change the design of amask used to form a pattern of the metal wiring layers of the elementregions. Therefore, the manufacturing process will not be complicatedand the manufacturing cost will not rise.

When the metal wiring layers are not present under the laser dicingregions 23-1, 23-2, the same effect can be attained if straight metalwiring layers are not forcibly arranged on the uppermost layers.

Second Embodiment

FIG. 4 shows two chips (semiconductor chips) 21-1, 21-2 which are formedclose to each other in a semiconductor wafer and a region 22 between thetwo chips 21-1 and 21-2 in an enlarged form, for illustrating asemiconductor device and a manufacturing method thereof according to asecond embodiment of the present invention. On the chip 21-1 side andthe chip 21-2 side of the region 22, an alignment mark 24 and test pads25-1, 25-2, 25-3 are respectively arranged. Further, a laser dicingregion 23 is straightly arranged in a portion near the central portionof the region 22 to avoid the alignment mark 24 and test pads 25-1,25-2, 25-3. A wiring layer is formed on the front surface layer of thelaser dicing region 23. The wiring layer is not used to make anelectrical connection but used as a dummy pattern (dummy wiring layer)which makes a laser beam application region uniform and permits thelaser beam to be easily absorbed. For example, the dummy wiring layer isformed by using the same layer as metal wiring layers used in elementregions of the chips 21-1, 21-2 together with the alignment mark 24 andtest pads 25-1, 25-2, 25-3.

When the semiconductor wafer is divided into the discrete chips 21-1,21-2, a laser beam is applied onto the laser dicing region (metal wiringlayer) 23 to melt and cut the laser dicing region. At the time ofmelting and cutting, the focusing position of the laser beam is set onthe uppermost layer by use of a lens and the laser beam is applied tomelt and cut the wafer. Further, after the focusing position of a laserbeam is set on the internal portion of the wafer and the laser beam isapplied to form a melt processing region due to multiphoton absorption,the wafer can be divided into discrete chips by cracking or stretching adicing film.

With the above configuration and manufacturing method, since the dummywiring layer (metal wiring layer) is formed on the uppermost layer ofthe laser dicing region 23 and the surface state thereof is uniform, thequality of the finished product will not vary. Further, since the metalwiring layer tends to absorb the laser beam, the cutting property in thelaser dicing step can be improved. Of course, since the wafer is dividedby melting, there is no possibility that chippings occurring in thedicing step in which a mechanical grinding process using a blade isperformed will occur. Further, focusing and power adjusting of the laserdicing device can be, easily attained. In addition, since the alignmentmark 24, test pads 25-1, 25-2, 25-3 and dummy wiring layer are formed byuse of the same layer as the metal wiring layers used in the elementregions in the chips 21-1, 21-2, it is only necessary to change thedesign of a mask used to form a pattern of the metal wiring layers ofthe element regions. Therefore, the manufacturing process will not becomplicated and the manufacturing cost will not rise.

When the metal wiring layer is not present under the laser dicing region23, the same effect can be attained if a straight metal wiring layer isnot forcibly arranged on the uppermost layer.

Third Embodiment

FIG. 5 shows two chips (semiconductor chips) 21-1, 21-2 which are formedclose to each other in a semiconductor wafer and a region 22 between thetwo chips 21-1 and 21-2 in an enlarged form, for illustrating asemiconductor device and a manufacturing method thereof according to athird embodiment of the present invention. In the third embodiment, in acase where it is difficult to shift an alignment mark 24 or test pads25-1 to 25-5, laser dicing regions (metal wiring layers) 23-1, 23-2 areadequately bent and arranged to avoid the arranged mark and pads.

A laser dicing device can freely move the application position of alaser beam in XY directions. Therefore, when the semiconductor wafer isdivided into the discrete chips 21-1, 21-2, a laser beam is applied ontothe bent metal wiring layers to melt and cut the laser dicing regions.Further, after the focusing position of a laser beam is set on theinternal portion of the wafer and the laser beam is applied to form amelt processing region due to multiphoton absorption, the wafer can bedivided into discrete chips by cracking or stretching a dicing film.

With the above configuration and manufacturing method, since the dummywiring layers (metal wiring layers) are formed on the laser dicingregions 23-1, 23-2 and the surface states thereof are uniform, thequality of the finished product will not vary. Further, since the metalwiring layer tends to absorb the laser beam, the cutting property in thelaser dicing step can be improved. Of course, since the wafer is dividedby melting, there is no possibility that chippings occurring in thedicing step in which a mechanical grinding process using a blade isperformed will occur. Further, focusing and power adjusting of the laserdicing device can be easily attained. In addition, since the alignmentmark 24, test pads 25-1 to 25-5 and dummy wiring layers are formed byuse of the same layer as the metal wiring layers used in the elementregions in the chips 21-l, 21-2, it is only necessary to change thedesign of a mask which is used to form a pattern of the metal wiringlayers of the element regions. Therefore, the manufacturing process willnot be complicated and the manufacturing cost will not rise.

When the metal wiring layers are not present under the laser dicingregions 23-1, 23-2, it is not necessary to forcibly arrange the bentwiring layers on the uppermost layers.

A case wherein the two dicing line regions are bent and arranged isexplained as an example, but it is of course possible to bend andarrange one dicing line region.

Fourth Embodiment

FIG. 6 shows two chips (semiconductor chips) 21-1, 21-2 which are formedclose to each other in a semiconductor wafer and a region 22 between thetwo chips 21-1 and 21-2 in an enlarged form, for illustrating asemiconductor device and a manufacturing method thereof according to afourth embodiment of the present invention. In the fourth embodiment, apolyimide film (which is formed of a polyimide-series material or is alaser beam absorbing film of the same kind) 26 is formed in a region 22.

Generally, in a semiconductor device with respect to which blade dicingis performed, the polyimide film on the region 22 is previouslyselectively removed in order to prevent generation of cutting chips andseparation of a surface protection film of polyimide formed on theelement region. However, in the fourth embodiment, the polyimide film 26formed on the element region is intentionally formed to extend over theregion 22.

With the above configuration and manufacturing method, the polyimidefilm (formed of a polyimide material or a material of the same kind) isapparently observed non-uniform since the underlying layer istransparent. However, since it absorbs the laser beam, a cutting processcan be uniformly performed and the cutting property in the laser dicingstep can be improved. Further, since the polyimide film is formed byextending a film used as a surface protection film of the elementregion, the manufacturing process will not be complicated and themanufacturing cost will not rise.

In the above explanation, the polyimide film (which is formed of apolyimide-series material or is a laser beam absorbing film of the samekind) 26 is formed on the entire surface of the region 22 between thechips 21-1 and 21-2. However, it is also possible to selectively arrangethe film only on the laser application region, that is, laser dicingregion 23.

Fifth Embodiment

FIG. 7 shows two chips. (semiconductor chips) 21-1, 21-2 which areformed close to each other in a semiconductor wafer and a region 22between the two chips 21-1 and 21-2 in an enlarged form, forillustrating a semiconductor device and a manufacturing method thereofaccording to a fifth embodiment of the present invention. In the fifthembodiment, a sheet-Like film (laser absorbing member) 27 which absorbsa laser beam is closely attached to and formed on the region 22.

Laser dicing is performed with respect to the semiconductor wafertogether with the above film.

With the above configuration and manufacturing method, basically thesame operation and effect as those of the first to fourth embodimentscan be attained.

It is possible to form an opening 28 in a position corresponding to analignment mark 24 at the time of dicing, if necessary. Further, insteadof the sheet-like film 27, a coating film or a film cured after coatinga liquid-form material or a film electro-chemically formed can be used.The above film or coating film can be selectively formed on the region22 or can be formed on the entire surface of the wafer if it is formedof a material which can be removed after the dicing process.

Sixth Embodiment

FIG. 8 shows two chips (semiconductor chips) 21-1, 21-2 which are formedclose to each other in a semiconductor wafer and a region 22 between thetwo chips 21-1 and 21-2 in an enlarged form, for illustrating asemiconductor device and a manufacturing method thereof according to asixth embodiment of the present invention. In the sixth embodiment, forexample, when bumps 28-1A, 28-1B, . . . , 28-2A, 28-2B, . . . are formedon external electrodes of semiconductor elements formed in the elementregions of the chips 21-1, 21-2, barrier metal layers provided betweenthe bumps 28-1A, 28-1B, . . . 28-2A, 28-2B, and the external electrodeso,f the semiconductor elements are arranged on laser dicing regions23-1, 23-2.

With the above configuration and manufacturing method, basically thesame operation and effect as those of the first to fourth embodimentscan be attained.

In FIG. 8, a case wherein the arrangement of the laser dicing region isthe same as that shown in FIG. 3 is explained as an example, but thearrangement as shown in FIG. 4 or 5 can be applied in the same manner.

Seventh Embodiment

FIGS. 9 and 10 show a laser dicing step, for illustrating asemiconductor device and a manufacturing method thereof according to aseventh embodiment of the present invention. The laser dicing stepaccording to the seventh embodiment can be applied to any one of thelaser dicing steps in the first to sixth embodiments.

First, as shown in FIG. 9, the rear surface of a semiconductor wafer 32is affixed to a dicing film 35 in order to make a cut in the frontsurface layer of the wafer 32. Then, the focusing position of a laserbeam is set on the uppermost layer (or on the front surface layer side)by use of a lens (condenser lens) 31 and the laser beam is applied to adicing region 33 on the element region side to make an extremely shallowcut and thus form a cut region 34. The dicing region 33 corresponds toone of the laser dicing regions 23-1, 23-2 and 23 in the first to sixthembodiments and the laser beam is applied to a portion other than thealignment mark and test pads.

After formation of the cut region 34, as shown in FIG. 10, the focusingposition of the laser beam is set on the internal portion (on the deeplayer side) of the wafer 32 and the laser beam is applied to the wafer32 from the rear surface side of the wafer 32 via the dicing film 35 toform a melt processing region 36 due to multiphoton absorption along thecut region 34. Then, the wafer is discretely divided.

Thus, by separately performing the laser dicing process twice for thesurface layer side and for the deep layer side, since laser power whenthe cut region 34 is formed is used to make a cut only in the surfacelayer portion and can be made relatively low, a cut by the laser beam issmall and a region required for dicing can be made relatively small.Further, since laser power used when the melt processing region 36 isformed can also be made low, unexpected destruction such as separationof the insulating film and layer-layer separation of the wiring layersoccurring at the time of dividing can be suppressed.

When carrying out the laser dicing step twice for the surface layer sideand for the deep layer side, it is possible to use two laser dicingdevices or one laser dicing device which can be used for both of thesteps.

Eighth Embodiment

FIG. 11 shows a laser dicing step, for illustrating a semiconductordevice and a manufacturing method thereof according to an eighthembodiment of the present invention. In the eighth embodiment, thedicing process which is performed in two steps in the seventh embodimentis performed in one step. That is, the focusing position of a laser beamis set on the uppermost layer (front surface layer side) by use of alens (condenser lens) 31-1 and the laser beam is applied from theelement forming surface side of a wafer 32, and at the same time, thefocusing position of a laser beam is set on the internal portion (deeplayer side) of the wafer 32 by use of a lens (condenser lens) 31-2 andthe laser beam is applied thereto from the rear surface side of thewafer 32 via a dicing film 35. Thus, a cut region 34 and melt processingregion 36 due to multiphoton absorption are formed substantially at thesame time and then the wafer is discretely divided.

With the above configuration and manufacturing method, substantially thesame operation and effect as those of the seventh embodiment can beattained.

Although metal wiring layers, polyimide films or laser absorptionmembers are not formed on the rear surface side of the wafer 32, thequality of the finished product will not vary since no semiconductorelements are present on the rear surface side and the surface state isuniform. Further, substantially no influence is given to the elementregion even if laser beam power is increased to some extent.

Ninth Embodiment

FIG. 12 shows a laser dicing step, for illustrating a semiconductordevice and a manufacturing method thereof according to a ninthembodiment of the present invention. In the ninth embodiment, the dicingprocess which is performed in two steps in the seventh embodiment isperformed in one step. That is, the focusing position of a laser beam isset on the uppermost layer (front surface layer side) by use of a lens(condenser lens) 31-1 and the laser beam is applied from the elementforming surface side of a wafer 32, and at the same time, the focusingposition of a laser beam is set on the internal portion (deep layerside) of the wafer 32 by use of a lens (condenser lens) 31-2 and thelaser beam is applied thereto. Thus, a cut region 34 and melt processingregion 36 due to multiphoton absorption are formed substantially at thesame time and then the wafer is discretely divided.

With the above configuration and manufacturing method, substantially thesame operation and effect as those of the seventh and eighth embodimentscan be attained.

In the seventh to ninth embodiments, a case wherein the wafer is dividedonly by laser dicing is explained as an example, but the laser dicingprocess can be performed not to completely divide the wafer and then thewafer 32 can be divided into discrete chips by cracking or stretching adicing film 35.

Further, the laser dicing process is performed as trimming and the wafercan be finally divided by normal blade dicing.

As described above, according to one aspect of this invention, asemiconductor device with high quality can be attained.

Further, a semiconductor device manufacturing method which can improvethe cutting property in the laser dicing step and the manufacturingyield can be attained.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1-17. (canceled)
 18. A method of manufacturing a semiconductor device comprising: applying a laser beam to a semiconductor wafer except an alignment mark and testing pads formed in each region between semiconductor chips of the semiconductor wafer, and dividing the semiconductor wafer into discrete semiconductor chips.
 19. A method of manufacturing a semiconductor device comprising: focusing a laser beam on a front surface layer side of a dicing line region, applying a laser beam to a semiconductor wafer except an alignment mark and testing pads formed in each region between semiconductor chips to form a cut region shallower than thickness of the semiconductor wafer, focusing a laser beam on a deep layer side of the semiconductor wafer corresponding in position to the cut region, applying a laser beam to the semiconductor wafer except the alignment mark and testing pads formed in each region between the semiconductor chips to form a melt processing region due to multiphoton absorption in the semiconductor wafer, and dividing the semiconductor wafer into discrete semiconductor chips.
 20. The semiconductor device manufacturing method according to claim 19, wherein forming the melt processing region is to apply the laser beam from a rear surface side of the semiconductor wafer via a dicing film.
 21. The semiconductor device manufacturing method according to claim 19, wherein forming the melt processing region is to apply the laser beam from an element region side of the semiconductor wafer.
 22. The semiconductor device manufacturing method according to claim 19, wherein the laser beam is applied to the region between the semiconductor chips in a straight form.
 23. The semiconductor device manufacturing method according to claim 19, wherein the laser beam is applied to the region between the semiconductor chips in a bent form.
 24. A method of manufacturing a semiconductor device comprising: applying a laser beam focused on a front surface layer side of a dicing line region to a semiconductor wafer except an alignment mark and testing pads formed in each region between semiconductor chips of the semiconductor wafer and applying a laser beam focused on an internal portion of the semiconductor wafer to the semiconductor wafer except the alignment mark and testing pads formed in each region between the semiconductor chips of the semiconductor wafer to form a cut region on the front surface layer side of the semiconductor wafer and a melt processing region due to multiphoton absorption on the deep layer side of the semiconductor wafer, and dividing the semiconductor wafer into discrete semiconductor chips.
 25. The semiconductor device manufacturing method according to claim 24, wherein the laser beam is applied to the region between the semiconductor chips in a straight form.
 26. The semiconductor device manufacturing method according to claim 24, wherein the laser beam is applied to the region between the semiconductor chips in a bent form. 